Disinfection Measures Research Articles

Проблемы дезинфектологического обеспечения населения в пандемическом периоде инфекции СOVID-19 в Республике Молдова

The principles of organizing and implementing anti-epidemic, including disinfectological measures for COVID-19 infection were studied, and the results of the state of readiness of interested services in the localization and elimination of focuses of coronavirus infection were presented. It was noted that the untimely solution of existing problems of a socio-economic nature contributed to the development of the pandemic process of COVID-19 infection. In the initial period of the development of the pandemic in most countries of the world, including Moldova, the system for monitoring and actively detecting cases of the population of COVID-19 did not work. Lack of disinfection services and insufficiently trained disinfectologists lead to untimely and poor-quality disinfection measures. The role of the disinfectological service in ensuring the epidemiological well-being of the population is argued. The necessity of creating a new, comprehensive system for protecting the country’s population from especially dangerous infectious diseases has been substantiated. Keywords: disinfection measures, biocides, treatment and prevention organizations, pandemic process, technologies, methods, forces and means, provision, infectious diseases, COVID-19 infection

Exploring COVID-19 patients\u2019 experiences of psychological distress during the disease course: a qualitative study

BackgroundThe Coronavirus Disease 2019 (COVID-19) is an emerging disease with many unknown clinical and therapeutic dimensions. Patients with COVID-19 experience a variety of psychological problems during the disease. Understanding patients’ mental condition and their distress during the disease is the first step to help these patients. So, the aim of this study was to explain COVID-19 patients’ experiences of psychological distress during the disease course.MethodsThe present qualitative research was conducted in Iran from April 2020 to April 2021 using the conventional content analysis method. The participants included patients with COVID-19, selected by the purposeful sampling method. Data was collected through 34 telephone and in-person interviews and analyzed based on the method proposed by Lundman and Graneheim.ResultsQualitative data analysis led to the emergence of sources of psychological distress as the main theme as well as seven categories and seven sub-categories. The categories were the disease’s nature (the subcategories of disease’s unknown dimensions, and disease severity), the anxiety caused by preventive behaviors (the subcategories of quarantine, worry about transmitting the infection to others and obsessive thoughts related to disinfection measures), the inefficient management by the health system (the subcategories of poor health care condition and lack of spiritual care), death anxiety, stigma, anxiety after recovery, and sleep pattern disturbance.ConclusionPatients with COVID-19 experience great psychological distress during the acute phase of the disease or even long after recovery. It is suggested that psychological and spiritual counseling, as a key element of treatment and support for these patients, is provided to patients in the acute phase of the disease, as well as after recovery. National and local media should boost awareness about the disease as a dangerous yet preventable and curable infectious disease. People should follow health instructions and leave their seeing the disease as a taboo.Trial registration numberNot applicable.

Внедрение информационных технологий на предприятии дезинфекционного профиля на примере ГУП МГЦД

In accordance with the national strategy "Sanitary Shield of the Country – Safety for Health," tasks were set for the analysis and assessment of risks in the field of biological safety. To do this: the Moscow City Disinfection Center is connected to a single dispatch system of the UNIT of the Department of Housing and Communal Services of Moscow, an Algorithm for working on the UNIT portal has been developed and uniform deadlines and procedure for fulfilling applications have been determined, the form of primary documentation has been determined. A unit is organized – the Unified Information and Analytical Center, whose tasks include organizing and conducting a single centralized reception, analysis and processing of incoming information (applications for unscheduled disinfection, deratization and disinsection, summary of rodent bites), generation and compilation of reports, as well as consulting support for real-time requests and appeals of the population, customers of the State Unitary Enterprise of the Moscow State Central Executive Committee, regulatory bodies through all available communication channels (telephone, e-mail, etc.). The scoring information system of assessment of a sanitary and sanitary and hygienic condition of objects is developed: apartment houses of the city of Moscow with the territories adjoining to them. The introduction of integrated work of these systems as a whole will allow organizations of the disinfection profile: to reduce the cost of deratizations, to reduce the number of disinfectants without reducing the quality of work, to avoid the excessive use of poisoned decoys, which will dramatically increase public health and safety of the population, as well as reduce the burden on the environment of the city of Moscow. Keywords: sanitary shield of the country, information and analytical center, scoring system of assessment of sanitary and epidemiological condition, electronic systems of rodent monitoring, biological safety, biological risk assessment, biological risk analysis, information support of disinfection activities, digitalization of disinfection measures.

Дезинфекция в общественных местах и транспорте как способ предотвращения распространения COVID-19

The article addresses to the epidemiological characteristics of the SARS-CoV-2 coronavirus. It covers detailed features and ways of coronavirus infection spreading in public venues, factors that affect the viability of the Coronaviridae family viruses, and the infection after-effects for people. Methodological and technical means of processing public transport and crowded places in the context of the spread of coronavirus infection (COVID-19) analysis has been carried out. The assessment of inactivating effectiveness of the basic chemical groups of disinfectants (oxygen-active; chloactive; cationic surfactants) is presented. The features of air masses and surfaces disinfection by the ultraviolet irradiation method are described. Special aspects and factors influencing the installations quality are considered, recommendations for the use of UV emitters of various types are given. The given study presents the general concept and current requirements for disinfection measures in public venues and transport in the context of coronavirus infection spreading. Keywords: COVID-19, coronavirus SARS-CoV-2, disinfection, novel coronavirus infection, sanitary epidemic control measures, transport, public venues.

Mechanisms and ways of transmission of SARS-CoV-2 coronavirus infection

The relevance of the problem. A new coronavirus infection caused by the SARS-CoV-2 virus has created an emergency situation of international importance. The incidence of it is characterized by a rapid spread across all countries, high morbidity rates, severe complications and mortality. Despite the fact that there are currently vaccines, it is not yet possible to stop the infection. Of particular importance as a preventive measure is the impact on the second link of the epidemic process. In this connection, obtaining objective data on the mechanisms and ways of spreading the SARS-CoV-2 virus will allow for more rational preventive measures and significantly reduce the risk of transmission of infection. The aim is to analyze current data on the mechanisms and ways of spreading the COVID-19 pathogen from available literature sources and to consider possible measures to influence the second link of the epidemiological chain in order to reduce the risks of infection. Materials and methods. The selection of peer-reviewed literature published from 2019 to 2021 was carried out. in the PubMed database and e-Library.ru, as well as links in articles. To obtain statistical data, the Internet resources of the World Health Organization (WHO), open data of Rospotrebnadzor, the Ministry of Health of the Russian Federation, Rosstat were used. Results. Analysis of scientific sources containing information on the mechanisms and ways of transmission of the new coronavirus infection COVID-19 indicates that the authors in their publications mention almost all the mechanisms and ways of transmission of this disease, but to varying degrees of their significance. The main mechanism of the spread of the SARS-CoV-2 virus is aspiration with airborne and airborne dust transmission routes. At the same time, the effect of contact, fecal-oral mechanisms is not excluded, the probability of the implementation of the vertical mechanism of transmission of the pathogen from the mother to the child, as well as the genital tract, is being studied. An important measure for the prevention of a new infection is the impact on the second link of the epidemic process, especially ensuring the highly efficient operation of ventilation and air conditioning systems in medical institutions and public places with a massive crowd of people, as well as compliance with personal preventive measures and disinfection measures.

A novel pathogenic Colletotrichum species for rhizome rot disease of Polygonatum kingianum

Rhizome rot disease is one of the main disease of planted Polygonatum kingianum. In this study, six strains of pathogenic fungus was isolated from P. kingianum samples with rhizome rot disease collected from six counties in Yunnan province. Its pathogenicity was confirmed by inoculation to healthy P. kingianum rhizome according to Koch's postulates. The colonies of the isolated fungi on potato dextrose agar(PDA) were orange with abundant crescentic conidia which were eseptate with a mean size of 19. 3-24. 9 μm×5. 2-5. 9 μm and a L/W ratio of 3. 4-4. 5. There was an oil ball in the center of the conidium. It's easy to see setae on PDA colony.The phylogenetic tree based on ITS, GAPDH, CHS-1, HIS3, ACT, and TUB2 sequences by maximum likelihood(ML) method indicated that the pathogenic fungus for P. kingianum rhizome rot disease was clustered into the clade of Colletotrichum spaethianum species complex, and was close to C. spaethianum. However, there were some differences in morphological and genetic characteristics between the pathogenic fungus and C. spaethianum. Therefore, the pathogenic fungus for rhizome rot disease of P. kingianum was identified as a new Colletotrichum species named C. kingianum. The disease spreads primarily due to the plantation of infected seedlings of P. kingianum. It is necessary to choose healthy seedlings and take rigorous disinfection measures for the disease prevention.

Study on Shock Disinfection in a Fire Extinguishing Water Supply System

The biofilms generated in a fire extinguishing water supply system can cause corrosion and a reduction in the water supply capacity; thus, degrading the system performance. To mitigate microbial corrosion, appropriate disinfection measures are necessary. In this study, the secondary addition of chlorine is employed to investigate the kinetics of chlorine decay, and shock disinfection is applied to investigate the removal efficiency of corrosion bacteria, and the microbial composition of a biofilm on the pipe wall was also clarified. The results show that the residual chlorine content in the secondary chlorination process was directly correlated with the decay rate of residual chlorine and the corrosion rate of the pipe wall. Additionally, the chlorine impact disinfection method could reduce the electrochemical corrosion phenomenon of the pipe wall. When the concentration of chlorine was 3 mg/L, the removal rate of corrosion bacteria was higher in 60 min than in 30 min. Specifically, most of the bacteria were inactivated in 60 min and the biofilm was severely damaged. Shock disinfection could significantly inactivate all microflora in the biofilm; the relative abundances of microflora varied significantly, while the change of microflora at the phylum level was insignificant. This study can provide theoretical support for the secondary addition of chlorine and shock disinfection in a fire extinguishing water supply system.

Occurrence and molecular characterization of Cryptosporidium spp. and Giardia duodenalis among captive mammals in the Bangladesh National Zoo.

Cryptosporidium and Giardia are protozoan parasites capable of causing gastrointestinal illness in humans and animals. The purpose of this research was to determine the occurrence, genetic characteristics, and zoonotic potential of Cryptosporidium spp. and Giardia duodenalis in captive mammals at the Bangladesh National Zoo. A total of 200 fresh fecal samples from 32 mammalian species were collected and examined for Cryptosporidium spp. using nested polymerase chain reaction (PCR) targeting the small subunit (SSU) rRNA gene and G. duodenalis targeting the β-giardin (bg), glutamate dehydrogenase (gdh), and triosephosphate isomerase (tpi) genes. The overall infection rates of Cryptosporidium and G. duodenalis among captive mammals in the zoo were 3.5% (7/200) and 5.5% (11/200), respectively. Five species/genotypes of Cryptosporidium (C. hominis, C. andersoni, C. muris, C. felis, and Cryptosporidium deer genotype) were identified. C. hominis was subtyped as IbA12G3 by sequence analysis of the glycoprotein 60 (gp60) gene. Multilocus genotyping of G. duodenalis revealed assemblages A, B, and D. Mixed infections of assemblages B and D and A and B were found in an Asiatic jackal and a Nilgiri langur, respectively. To our knowledge, this is the first report on the occurrence and genetic identity of the two parasites among zoo animals in Bangladesh. The results suggest that zoonotic Cryptosporidium spp. and G. duodenalis are maintained in and transmitted between captive mammals. Therefore, washing, cleaning, and disinfection measures should be implemented to reduce the spread of Cryptosporidium and G. duodenalis infections.

The assessment of microbiological and physicochemical characteristics in drainage waters of the Siriu dam

Based on the balneotherapeutic applications of mineral spring water and particularly sulphurous water, the aim of our research was to study the physicochemical and microbiological parameters of some drainage waters of Siriu dam that showed a strong hydrogen sulphide odour. In addition, due to the corrosive effect of some groups of microorganisms, such as iron-oxidizing bacteria and sulphatereducing bacteria, the present paper also aimed to detect their presence in order to signal the need for some disinfection measures. According to physicochemical analysis, there has been found an external drain that is suitable for use in balneotherapy, presenting a balanced content of mineral elements such as sulphur, calcium, silicon, chlorine and potassium. However, due to the presence of potentially toxic phytoplankton microorganisms such as Microcystis sp. and Phormidium sp. it is necessary to disinfect this water source before using it for any purpose. On the other hand, the identification of both sulphate-reducing bacteria and iron-oxidizing bacteria in the drainage waters of Siriu dam should be considered as an alarm signal as they may lead to bio-corrosion and deterioration of metallic or concrete structures, affecting the integrity of the dam and hydropower constructions.

Legionella contamination of a cold-water supplying system in a German university hospital - assessment of the superheat and flush method for disinfection.

SummaryIntroductionIn case of a contamination of water-supplying systems in hospitals with legionella, usually chemical disinfection measures are used for remediation. Unfortunately, it is reported, that these methods may not be sustainable, have an impact on water quality, and can even fail. As an alternative, the superheat and flush method does not need any special equipment, can be initiated in a short lead of time and does not affect the water quality. However, evidence on this disinfection measurement against legionella is lacking. We therefore investigated and report on the effectiveness and long-term results of the superheat and flush disinfection method.MethodsDuring routine periodical examinations, a rising count of legionella was detected in the cold-water supplying system at a German university hospital. Adapted to an analysis of risks, effort and benefit, the superheat and flush procedure was applied twice within 6 months.ResultsWhile 33 out of 70 samples had a higher legionella count than the legal threshold of 100 CFU/100 mL (CFU - Colony Forming Units) before the first disinfection was carried out, this number could be reduced to 1 out of 202 samples after the first intervention. Additionally, in contrast to previously published studies, the effect was long-lasting, as no relevant limit exceedance occurred during the following observation period of more than two years.ConclusionThe superheat and flush disinfection can provide an economic and highly effective measure in case of legionella contamination and should be shortlisted for an eradication attempt of affected water-supplying systems in hospitals.

A Shift to Human Body Temperature (37°C) Rapidly Reprograms Multiple Adaptive Responses in Escherichia coli That Would Facilitate Niche Survival and Colonization.

ABSTRACTOne of the first environmental cues sensed by a microbe as it enters a human host is an upshift in temperature to 37°C. In this dynamic time point analysis, we demonstrate that this environmental transition rapidly signals a multitude of gene expression changes in Escherichia coli. Bacteria grown at 23°C under aerobic conditions were shifted to 37°C, and mRNA expression was measured at time points after the shift to 37°C (t = 0.5, 1, and 4 h). The first hour is characterized by a transient shift to anaerobic respiration strategies and stress responses, particularly acid resistance, indicating that temperature serves as a sentinel cue to predict and prepare for various niches within the host. The temperature effects on a subset of stress response genes were shown to be mediated by RpoS and directly correlated with RpoS, DsrA, and RprA levels, and increased acid resistance was observed that was dependent on 23°C growth and RpoS. By 4 h, gene expression shifted to aerobic respiration pathways and decreased stress responses, coupled with increases in genes associated with biosynthesis (amino acid and nucleotides), iron uptake, and host defense. ompT, a gene that confers resistance to antimicrobial peptides, was highly thermoregulated, with a pattern conserved in enteropathogenic and uropathogenic E. coli strains. An immediate decrease in curli gene expression concomitant with an increase in flagellar gene expression implicates temperature in this developmental decision. Together, our studies demonstrate that temperature signals a reprogramming of gene expression immediately upon an upshift that may predict, prepare, and benefit the survival of the bacterium within the host.IMPORTANCE As one of the first cues sensed by the microbe upon entry into a human host, understanding how bacteria like E. coli modulate gene expression in response to temperature improves our understanding of how bacteria immediately initiate responses beneficial for survival and colonization. For pathogens, understanding the various pathways of thermal regulation could yield valuable targets for anti-infective chemotherapeutic drugs or disinfection measures. In addition, our data provide a dynamic examination of the RpoS stress response, providing genome-wide support for how temperature impacts RpoS through changes in RpoS stability and modulation by small regulatory RNAs.

Clostridioides difficile Infection in Patients with Chronic Kidney Disease: A Systematic Review.

Clostridioides difficile infection (CDI) is a health issue of utmost significance in Europe and North America, due to its high prevalence, morbidity, and mortality rate. The clinical spectrum of CDI is broad, ranging from asymptomatic to deadly fulminant colitis. When associated with chronic kidney disease (CKD), CDI is more prevalent and more severe than in the general population, due to specific risk factors such as impaired immune system, intestinal dysmotility, high antibiotic use leading to disturbed microbiota, frequent hospitalization, and PPI use. We performed a systematic review on the issue of prevention and treatment of CDI in the CKD population, analysing the suitable randomized controlled cohort studies published between 2000 and 2021. The results show that the most important aspect of prevention is isolation and disinfection with chlorine-based solution and hydrogen peroxide vapour to stop the spread of bacteria. In terms of prevention, using Lactobacillus plantarum (LP299v) proved to be more efficient than disinfection measures in transplant patients, leading to higher cure rates and less recurrent episodes of CDI. Treatment with oral fidaxomycin is more effective than with oral vancomycin for the initial episode of CDI in CKD patients. Faecal microbiota transplantation (FMT) is more effective than vancomycin in recurrent CDI in CKD patients. More large-sample RCTs are necessary to conclude on the best treatment and prevention strategy of CDI in CKD patients.

Оценка эффективности профилактических дезинфекционных мероприятий на основе комплексного анализа микробиома мест содержания служебных собак

The article presents the results of a qualitative and quantitative analysis of the microbiome of places where dogs of service breeds are kept, obtained under the conditions of rotation of medicines for an active substance. In the period from 2017 to 2021, dynamic observations were made to assess the effectiveness of preventive disinfection measures carried out in the cynological town. The object of the study was the micro-and mycoflora of more than 20 dog enclosures in two versions: before disinfection and after mechanical treatment and fine-drip irrigation with preparations recommended for disinfection of veterinary surveillance facilities. Using differential diagnostic nutrient media, representatives of different groups of microorganisms were isolated from the surfaces of inventory, poilushki, the floor and walls of the walking enclosures. A qualitative analysis of biodiversity revealed that microbial isolates are conditionally pathogenic microorganisms and can be potentially dangerous infectious agents. The results showed that disinfection measures were not sufficiently effective against the selected groups of microorganisms. Using elective nutrient media, cultures of yeast-like and mold-like micromycetes were isolated from the surfaces of walking enclosures. The analysis of the data showed that both decompositions, claimed to be effective against mold micromycetes, do not withstand the contaminating load. The method of small-drop irrigation used for processing the walking of the kennels of the cynological town turned out to be low-effective in relation to the isolated microbial and fungal isolates. Within the framework of compliance with the sanitary and hygienic regime, an algorithm for organizing preventive disinfection measures in the cynological unit has been developed, based on the well-coordinated interaction of support services: medical, logistics, sanitary and veterinary. The research conducted jointly with representatives of the veterinary and sanitary service, with cadets of the cynological faculty, is of great practical importance for the formation of the professional competence of future officers – specialists-cynologists, heads of cynological units. The developed recommendations make it possible to adjust the algorithm of sanitary and hygienic measures in the cynological town and are of great importance in solving health-saving issues and maintaining the number of dogs of service breeds. Keywords: preventive disinfection; sanitary-indicative microorganisms; micromycetes; health care of dogs; cynologists.

Effects of COVID-19 protective measures on the ophthalmological patient examination with an emphasis on gender-specific differences

ObjectiveIn response to the COVID-19 pandemic, strict hygiene and containment measures have been instituted in the clinical ophthalmological examination to prevent virus transmission. The aim of this study is to...

Disinfection Measures during COVID-19

Corona illness 2019 (covid-19) has been occured by widspread serious lung condition due to infection with newly emerging Corona virus 2 during 2019. The infection threatened people health world-wide. Covid2-19 started in China and caused an aggregate of few affirmed cases and few of them passing till end of sixth month. Infection occurs essentially through lung droplets and infect near by people. Individual to-individual infection occur by conveyance by droplets from hack, wheeze, drop inward breath, and infection through upper dry epithelium polluted by emissions of complete respiratory tract system of a infected individual had been demonstrated about corona spread. As infection advanced, a progression of intricacies will in general grow, particularly in fundamentally sick and immunocompromised patients. Neurotic investigations demonstrated delegate highlights of intense lung misery condition (ARDS) and involvement of different organs too. Nonetheless, no particular antiviral medications or immunizations are promptly accessible to the medical care of this deadly infection. The adequacy of some encouraging antibacterial should be examined to continuous health preliminaries. In this conditions, strong consideration, safety measures, and physical distansing are the lone preventive measuresfor protection against CORONA. To sanitize the climate, fundamentally compound bactericidal are being utilized powerfully. Notwithstanding, because of frenzy state, fear, and ignorance, individuals are utilizing it fiercely, which can adversely affect human wellbeing and climate. This audit examines the likely negative impact of disinfectants, whenever utilized improperly. Here, we will likewise talk about safe preventive choices as an option in contrast to strong utilization of sterilization strategies to battle against CORONA.

Disinfection Measures during COVID-19 for Dental Operatories

Background: In the dental health-care setups, the environmental object and surfaces are expected to be infected by the COVID virus wherein definite procedures are performed. Consequently, these objects and surfaces, particularly where COVID-19 patients are being treated, must be appropriately cleaned and sanitized to stop further spread. Objective: The present article is intended for providing protocols about the cleaning and disinfection of objects and surfaces in the circumstances of COVID-19 for Dental operatories. Methods: Studies evaluating the surface characteristics of the virus as well as effective disinfection measures have been documented. Results: Various chemicals in different concentrations have a virocidal effect. The devices introduced include used UV radiation and ozone. Conclusion: These changes in dental clinical practice are needed to save humanity by preventing further transmission of disease.

Constant Optical Power Operation of an Ultraviolet LED Controlled by a Smartphone.

Constant light power operation of an ultraviolet (UV) LED based on portable low-cost instrumentation and a monolithically integrated monitoring photodiode (MPD) has been reported for the first time. UV light irradiation has become one of the essential measures for disinfection and sterilization. Monitoring and maintaining a specified light power level is important to meet the criteria of sterilization. We built a module composed of a monolithically integrated UV LED and MPD, a transimpedance amplifier, an Arduino Uno card, a digital-to-analog converter and a Bluetooth transceiver. An Android App that we wrote remotely controlled the UV LED module via Bluetooth. The Arduino Uno card was programmed to receive demands from the smartphone, sent a driving voltage to the LED and returned the present MPD voltage to the smartphone. A feedback loop was used to adjust the LED voltage for maintaining a constant light output. We successfully demonstrated the functioning of remote control of the App, and the resultant UV LED measured power remained the same as the setting power. This setup can also be applied to visible or white LEDs for controlling/maintaining mixed light’s chromaticity coordinates or color temperature. With such controlling and internet capability, custom profiling and maintenance of precision lighting remotely would be possible.

Infection Control Practices in Orthodontics during COVID-19

Aim: To find out infection control practices among orthodontists in Punjab, Pakistan during COVID-19 pandemic. Methods: This cross sectional study was conceived from 1.6.2020 to 1.1.2021. A pre-designed proforma was used to find out the infection control practices in orthodontics. Each pre-designed proforma consisted of 10 questions about infection control. The pre-designed proforma was distributed among 50 orthodontists. The response rate was 100%. Results: The results showed that most of the orthodontists were up-dated and in practice of using proper infection control measures while COVID-19. Gloves, PPE, Protective eye wears and face shields were worn by most of the respondents. Most of them were using proper disinfection and sterilization measures. Conclusion: The knowledge and practices of infection control in orthodontics was appropriate and up to standards during COVID-19. Key words: Infection Control; Orthodontics

Incidence of Nosocomial Infections in Burns in The Surgery Department of The Reference Hospital Jason Sendwe in Dr Congo

Introduction: Data-t-on nosocomial infections in burns are rare then and yet they constitute therapeutic emergencies. The objective of this work was to determine the incidence, clinical and therapeutic aspects and the associated complications of nosocomial infections in people with burns from Sendwe HGR in the DRC. Methods: We carried out a longitudinal descriptive study during the period from January 1 to December 31, 2019. Our study population consisted of all patients hospitalized in the burns department of the HGR Sendwe during the study period. Results: The incidence of nosocomial infections in burns was 22.6%; the depth of the most important burn was the second superficial degree at 87.09%, the extent of the most important burn was between 0 and 10% i.e. a frequency of 38.76%, the site of the burn the more frequent was made of the association of upper limbs, lower limbs and head at 12.9%; the time to onset of nosocomial infections in burns was between the third day and the fifth day at 35.71%; electrolyte resuscitation fluid in burns was the combination of ringer lactate and physiological saline at 83.87%, the antibiotic most used in burns was the combination of metronidazole and cefotaxime at 67.74 %. Conclusion: The incidence of nosocomial infections in burns was high; essential hygiene measures, sterilization and disinfection measures for the equipment used should be maximized in order to further prevent these scourges.

Affordable measures to monitor and alarm nosocomial SARS-CoV-2 infection due to poor ventilation.

Since the coronavirus disease 2019 (COVID‐19) outbreak, the nosocomial infection rate worldwide has been reported high. It is urgent to figure out an affordable way to monitor and alarm nosocomial infection. Carbon dioxide (CO2) concentration can reflect the ventilation performance and crowdedness, so CO2 sensors were placed in Beijing Tsinghua Changgung Hospital's fever clinic and emergency department where the nosocomial infection risk was high. Patients’ medical records were extracted to figure out their timelines and whereabouts. Based on these, site‐specific CO2 concentration thresholds were calculated by the dilution equation and sites’ risk ratios were determined to evaluate ventilation performance. CO2 concentration successfully revealed that the expiratory tracer was poorly diluted in the mechanically ventilated inner spaces, compared to naturally ventilated outer spaces, among all of the monitoring sites that COVID‐19 patients visited. Sufficient ventilation, personal protection, and disinfection measures led to no nosocomial infection in this hospital. The actual outdoor airflow rate per person (Q c) during the COVID‐19 patients’ presence was estimated for reference using equilibrium analysis. During the stay of single COVID‐19 patient wearing a mask, the minimum Q c value was 15–18 L/(s·person). When the patient was given throat swab sampling, the minimum Q c value was 21 L/(s·person). The Q c value reached 36–42 L/(s·person) thanks to window‐inducted natural ventilation, when two COVID‐19 patients wearing masks shared the same space with other patients or healthcare workers. The CO2 concentration monitoring system proved to be effective in assessing nosocomial infection risk by reflecting real‐time dilution of patients’ exhalation.